BERLIN (Reuters) - Heavyweight champion Manuel Charr will not defend his WBA belt next week against American challenger Fres Oquendo after a ‘suspect’ doping test by the Syrian forced the fight to be canceled, his management said on Thursday.

Charr’s A sample from an Aug. 31 test showed “two suspect substances” and due to time constraints regarding the opening and testing of the B sample the bout was now canceled.

“I cannot explain it and I am asking myself how could it happen,” the fighter, who lives in Cologne, told the Koelner Express newspaper.

“I have never taken anything. I fought Vitali Klitschko and Alexander Povetkin, seven title fights and I was always a clean athlete. “Why should I take something before the fight against Fres Oquendo.”

The 33-year-old Charr (31-4) had won the WBA title against Russia’s Alexander Ustinov last year.